Hi,
We are planning to hike Mt Dana on Sept 29. Is it too late in the season?
Plan to start the hike around 7am. Will that be ok?
Should we expect thunderstorms at the summit?

Any other general precautions that we need to worry about?

We all are experienced hikers and have done many 10k+ hikes including Whitney. We wont get much of acclimatization for Mt Dana as we will be driving from San Francisco only the day prior. We will take Diamox from 2 days before so as to safeguard against it.

The only answers to your questions will come a few days before your hike. Check the weather. It if looks good, you should have no problems. if the weather looks iffy, there are lots of places I would rather be than on Mt Dana.

And if you don't feel well because of the altitude, there are lots of hikes lower down that will also entertain you.